# Yunnan University: Atlantic and Pacific SST gradients switch the Atlantic Niño–ENSO link on and off

- Published: 2026-11-05 06:20 UTC
- Section: Planet › Climate
- Tags: Atlantic Niño, ENSO, El Niño–Southern Oscillation, Walker circulation, sea surface temperature gradient, wind–evaporation–SST feedback, La Niña, Gill–Matsuno response, tropical Atlantic and Pacific
- URL: https://realtech.media/news/rt-2647a0d493390f2e62fac5ab_yunnan_university_atlantic/

**A study in The Innovation, based on a century of observations and model experiments, links the Atlantic Niño's effect on winter ENSO to tropical sea surface temperature gradients.**

![Yunnan University: Atlantic and Pacific SST gradients switch the Atlantic Niño–ENSO link on and off](https://sgzwpqqelzmajkcubgkl.supabase.co/storage/v1/object/public/rt-media/2026/11/1e2db6bd759a5473.jpg)
*NOAA, Wikimedia Commons, Public domain*

A team led by Yunnan University has identified what controls the link between the summer Atlantic Niño and the following winter's El Niño–Southern Oscillation (ENSO), according to a study in The Innovation (2026, vol. 7, issue 10) [1]. The authors combined more than a century of observations with model sensitivity experiments. They found that sea surface temperature (SST) gradients in the tropical Atlantic and Pacific determine whether the connection is active [1].

The relationship has strengthened in recent decades, but its mechanism had remained unclear [1]. In the observational record, the summer Atlantic Niño and the subsequent winter ENSO were significantly correlated in 1894–1925 and 1984–2009, but not in 1928–1981.

## Atlantic zonal and Pacific meridional gradients

The east–west (zonal) SST gradient over the tropical Atlantic is driven by the wind–evaporation–SST (WES) feedback; when the feedback weakens, the gradient weakens as well [1]. Under weak zonal gradients, the Gill–Matsuno-type response to an Atlantic Niño shows stronger ascending motion over the tropical western Atlantic than under strong gradients [1].

Over the eastern tropical Pacific, the north–south (meridional) SST gradient enhances anomalous descent. The rising and sinking branches together help establish a cross-basin Walker circulation between the tropical western Atlantic and the eastern Pacific [1]. This is the same kind of atmospheric loop that links the warm pool of the western Pacific with the cold eastern equatorial Pacific.

## Model experiments

Once the cross-basin circulation is in place, the enhanced Pacific Walker circulation contributes to the development of La Niña, and the Atlantic Niño–ENSO connection strengthens [1]. In the sensitivity experiments, the researchers modified the temperature gradients. The favorable configuration built up the cross-basin circulation, while the opposite configuration left the two oceans effectively decoupled [1].

The authors state that the study identifies new drivers of tropical Atlantic–Pacific linkages that are relevant to ENSO prediction [1]. They note that future work should further quantify how the temperature gradients of each basin contribute to cross-basin interactions.

## Sources

1. [The Innovation](https://doi.org/10.1016/j.xinn.2026.101502)
2. [EurekAlert](https://www.eurekalert.org/news-releases/1150211)

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Source: RealTech, realtech.media — https://realtech.media/news/rt-2647a0d493390f2e62fac5ab_yunnan_university_atlantic/